In general, the invention provides a magnetic head device and linear tape drive that increase the resonant frequency and the range of a servo system. In particular, the invention provides a magnetic head device comprising a magnetic head chip with multiple magnetic head elements that is a structural part of the fine positioning system which allows the magnetic head elements follow the data tracks on the linear magnetic tape. Consequently, weight is reduced thereby increasing the resonant frequency and servo bandwidth. In another embodiment, the invention provides a magnetic head comprising bimodal actuators that are formed into an S shape and displaced by applying voltage where the polarization direction is opposite from one end to the other. In particular, the head chip may remain stable and may be driven dynamically thereby allowing the mechanical resonance of the bimodal actuator (including the head chip) to increase to 1 kHz or higher.
Legal claims defining the scope of protection, as filed with the USPTO.
1. A magnetic head device for recording and playback of information on linear magnetic tape that includes tracks that extend in a lengthwise direction of the tape comprising: a magnetic head structure including a magnetic head chip comprising multiple magnetic head elements arranged in the lengthwise direction of the tape as the tape passes over the magnetic head chip and multiple magnetic head elements arranged in a direction across the tape as the tape passes over the magnetic head chip, wherein the magnetic head chip extends across a width of the tape such that the tape contacts a surface of the magnetic head chip as the tape passes over the magnetic head structure; and a fine positioning structure comprising twin bimodal actuators comprising a pair of opposing bimodal elements positioned on opposing sides of the magnetic head chip such that a distance between the pair of opposing bimodal elements corresponds approximately to a length of the magnetic head chip in a direction across the width of the tape, wherein the fine positioning structure is attached to the magnetic head structure and transfers the magnetic head chip across a track width, wherein one end of each of the bimodal elements is fixed and a free end of each of the bimodal elements is mechanically connected to the magnetic head chip and supports the magnetic head chip, and wherein the magnetic head elements are moved in a fine parallel motion across the track width by the fine positioning structure, wherein both ends of the magnetic head chip are mechanically bonded to each free end of the bimodal elements through a chip base, wherein the chip base comprises an elastic piece displaced by displacement of the free ends of the bimodal elements.
2. The device of claim 1 , wherein a front surface of the magnetic head chip is curved, a radius of curvature of the front surface in a tape feeding direction is significantly larger than a curvature in a width direction, and the magnetic tape contacts a ridge line of the magnetic chip.
3. The device of claim 1 , wherein the chip base comprises an elastic piece made of resin that is impregnated with fiber.
4. The device of claim 1 , wherein each of the bimodal elements has a side that is connected to the magnetic head chip as a contact ground.
5. The device of claim 1 , wherein the length of the magnetic head chip is selected so that the magnetic head chip contacts an entire width of the magnetic tape in every position corresponding to recording or playback position.
6. The device of claim 1 , further comprising a rough positioning structure attached to the magnetic head structure that transfers the magnetic head structure across the track width, wherein the rough positioning structure comprises opposing walls maintained at a predetermined space from each other and guide a flexible wire substrate for output from the magnetic head chip, and wherein the magnetic head structure is transferred across the track width by the rough positioning structure without being impeded by the output wires from the magnetic head chip.
7. The device of claim 1 , wherein a front side of the magnetic head chip is a flat surface, a face of the magnetic head chip is curved in the tape feeding direction, and the magnetic tape contacts a ridge line of the magnetic head chip.
8. The device of claim 1 , wherein application of a voltage to each of the bimodal elements displaces the twin bimodal actuator and forms the twin bimodal actuator into an S shape, wherein a polarization direction is opposite at one end of the bimodal elements, and wherein another end of each of the bimodal elements is connected to both ends of the magnetic head chip.
9. The device of claim 8 , wherein both ends of the bimodal actuator and the magnetic head chip are connected through a flexible connection having a bent part.
10. The device of claim 9 , wherein the voltage applied to each of the bimodal elements of the bimodal actuators is controlled individually.
11. The device of claim 8 , wherein the voltage applied to each of the bimodal elements of the twin bimodal actuator is controlled individually.
12. A linear tape drive system that uses linear tape with multiple magnetic tracts extending in a lengthwise direction formed across the width of a magnetic tape comprising: a tape cassette around which the magnetic tape is wound; a magnetic head device comprising a magnetic head structure and a fine positioning structure to transfer the magnetic head structure across a track width; and a magnetic tape guide that guides the magnetic tape drawn from the tape cassette to the magnetic head device; wherein the magnetic head structure comprises a magnetic head chip comprising multiple magnetic head elements arranged in the lengthwise direction of the tape as the tape passes over the magnetic head chip and multiple magnetic head elements arranged in a direction across the tape as the tape passes over the magnetic head chip, wherein the magnetic head chip extends across a width of the tape such that the tape contacts a surface of the magnetic head chip as the tape passes over the magnetic head structure and the fine positioning structure is attached to the magnetic head structure, and wherein the fine positioning structure comprises twin bimodal actuators comprising a pair of opposing bimodal elements positioned on opposing sides of the magnetic head chip such that a distance between the pair of opposing bimodal elements corresponds approximately to a length of the magnetic head chip in a direction across the width of the tape, wherein one end of each of the bimodal elements is fixed and a free end of each of the bimodal elements is mechanically connected to the magnetic head chip and supports the magnetic head chip, wherein both ends of the magnetic head chip are mechanically bonded to each free end of the bimodal elements through a chip base, wherein the chip base comprises an elastic piece displaced by displacement of the free ends of the bimodal elements.
13. The system of claim 12 , wherein a front surface of the magnetic head chip is curved, a radius of curvature of the front surface in the tape feeding direction is significantly larger than a curvature in a width direction, and the magnetic tape contacts the ridge line of the magnetic chip.
14. The system of claim 12 , wherein the twin bimodal actuator is formed into an S shape by applying a voltage to the bimodal elements, wherein a polarization direction is opposite at one end of the bimodal elements and another end of each of the bimodal elements is connected to both ends of the magnetic head chip.
15. The system of claim 12 , wherein each of the bimodal elements has a side that is connected to the magnetic head chip as a contact ground side.
16. The system of claim 12 , wherein the length of the magnetic head chip is selected so that the magnetic head chip contacts an entire width of the magnetic tape in every position corresponding to recording or playback position.
17. The system of claim 12 , further comprising a rough positioning structure attached to the magnetic head structure that transfers the magnetic head structure across the track width, wherein the rough positioning structure comprises opposing walls maintained at a predetermined space from each other that guide a flexible wire substrate for output from the magnetic head chip, and wherein the magnetic head structure is transferred across the track width by the rough positioning structure without being impeded by output wires from the magnetic head chip.
18. The system of claim 12 , wherein a front side of the magnetic head chip is a flat surface, a face of the magnetic head chip is curved in the tape feeding direction, and the magnetic tape contacts a ridge line of the magnetic head chip.
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January 24, 2005
April 15, 2008
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